The build is the latest preview from the 19H1 development branch, making it a preview of the next feature update for Windows 10 after the October 2018 Update. Since we're now just weeks away from the October 2018 Update being generally available, 19H1 should actually show up in the standard Fast ring pretty soon.

Today's build doesn't contain any new front-facing features, but it does include a number of fixes, improvements, and known issues. Here's what got fixed and improved:

We fixed an issue resulting in Narrator text to speech not making sense when reading Narrator’s Quick Start pop up in Japanese.

We fixed an issue resulting in app icons sometimes becoming invisible in the taskbar in recent flights.

We fixed an issue that could result in an IME not working in Microsoft Edge the first time it was launched.

We fixed an issue resulting in WebView controls potentially not responding to keyboard.

Rolling out this week, along with more bug fixes, we have added a “Preview” tag to Your Phone app as we continue to finetune the based on your feedback. Keep it coming via Feedback Hub.

Task Manager is not reporting accurate CPU usage. This should be fixed in the next flight.

Arrows to expand “Background processes” in Task Manager are blinking constantly and weirdly.

There's also one known issue for developers:

If you install any of the recent builds from the Fast ring and switch to the Slow ring – optional content such as enabling developer mode will fail. You will have to remain in the Fast ring to add/install/enable optional content. This is because optional content will only install on builds approved for specific rings.

You'll need to be on the Skip Ahead subset of the Fast ring to get this, and if you're not already on it, it's too late, as there's limited availability. As noted above though, we should start seeing 19H1 builds in the standard Fast ring soon enough, and hopefully we'll then start hearing about the major new features that are coming.